By Mike Wiser, Reporter

DES MOINES, Iowa  President Barack Obama is set to be back in Iowa for two campaign rallies Saturday in advance of next week's Democratic National Convention in North Carolina.

The president's first stop is an afternoon event at the Living History Farms in Urbandale, where Grammy-winning musician Chris Cornell will perform. The president then heads west for an evening rally in Sioux City. Campaign officials say Obama's remarks will focus on the economy and the middle class.

It will be Obama's seventh and eighth stops in the state since January and the second one this week. On Tuesday, Obama held an event for a crowd of about 6,000 at Iowa State University in Ames.

The frequency of visits shows how important Iowa and its six electoral votes are to both campaigns. Republican presidential nominee Mitt Romney has been in Iowa six times since January. "It's always a good thing for the state (to have candidates visit), particularly for young voters," said Christopher Larimer, a political-science professor at the University of Northern Iowa. "It shows that every vote does matter."

"President Obama is desperate to hold onto the state that launched him to the White House, but four years after 'hope and change' inspired Iowans, they're only left with disappointment," Iowa campaign spokesman Shawn McCoy said. "Iowans know that Gov. Romney spent a lifetime creating good, well-paying jobs, helping start and build successful businesses and turning around failing ones."

Iowa Attorney General Tom Miller, a Democrat who is part of Iowa's delegation headed to North Carolina, said "it's not desperation at all." "It's a reflection of how much he cares about Iowa," Miller said. "Iowa got him started, he got to know the people better here than probably any other state, except for his home state of Illinois."

Larimer believes the visits are indicative of how close the polls in Iowa show the race to be, which looks more like Iowa in past elections.In 2008, Obama won the state by 9 percentage points, which Larimer calls "an aberration." The difference was 146,561 votes out of more than 1.5 million cast.

By contrast, records from the Iowa Secretary of State's Office show that George W. Bush won the state by two-thirds of a point in 2004, and in 2000, Gore won by a one-third of a point. Those differences being 10,059 votes out of 1.5 million cast and 4,140 votes about of more than 1.3 million cast, respectively.

Larimer said it's unlikely that either Obama or Romney will be able break out by November. "I don't know how many true independents are left," he said. "To lock it up, they need to hope that someone in the other campaign screws up. Or maybe there's some good economic news for Obama."